In the past, we've said that your website doesn't need to meet the standards for web programming set forth by the W3C organization. W3C creates the guidelines for the perfect world of the web, and they are pretty tough to meet.
In general, you should try your best to follow their guidelines because they result in cleanly programmed websites that work well with web browsers and search engines. The W3C guidelines also help us all to achieve faster websites, mobile websites, and an overall faster internet.
If ever a website were to "go green" by today's standards, it would be to follow the W3C standards.
However, it's easy to lose sight of those guidelines if you are programming your own website, using a content management system or even a program like Dreamweaver. You might even want to throw those guidelines out the...